Largely known in the art is the use of sealed capsules usually containing a single-dose amount of raw materials that, as a consequence of steam or water under pressure being fed into the capsules themselves, produce a beverage.
An example of a traditional capsule of this kind, which is disclosed in the patent publication EP-A-0 521 510, comprises a body portion having a slightly flared shape, which is made of plastics moulded integrally with the bottom wall thereof, the latter being in the shape of a planar disk with a plurality of reduced-thickness zones and supporting a filter on the inner face thereof. This capsule is completed by an upper wall formed by a membrane. At the moment of its use, the capsule is loaded in a machine, where said upper wall is perforated so as to enable water under pressure to be let into the capsule, while another piercing device provides a plurality of orifices in said reduced-thickness zones of the bottom wall. The beverage practically flows out of the capsule through said orifices in a substantially uncontrolled manner, particularly in the case of capsules containing raw materials in powder form, such as for instance ground coffee of the non-instant kind, which oppose a certain resistance to the flow of water under pressure.
This is basically the reason why machines used in conjunction with capsules of the traditional type must comprise conduits to deliver the beverage from the point at which it flows out of the capsule up to the cup or other vessel in which the beverage itself is due to be received for drinking. In this connection, see for instance the patent publication EP-A-1 034 729. These conduits, however, are subject to soiling, owing to it being quite difficult and awkward—if not right away impossible—for them to be regularly and correctly cleaned. Particularly in the case of a not so frequent use of the machine, when beverages with a certain content of fatty substances (e.g. coffee and meat stock or consommé) are prepared, there exists a real risk for these substances to eventually ferment and grow rancid in the conduits, and this is certainly a development that people due to drink the beverages flowing out of said conduits are quite likely to find rather unpleasant.
Another example of the related state of the art is the machine disclosed in the patent publication U.S. Pat. No. 5,472,719, in which the piercing device used to perforate the bottom wall of the capsule performs at the same time also as a collecting device for the beverage flowing out through the orifices created by the same device. Some of the embodiments discussed in the above-cited patent call for these combined piercing and collecting devices to be provided as disposable one-way parts, in the sense that it is contemplated that a new device has to be used for each single capsule. This, however, further to determining an obvious increase in costs, gives rise to readily appreciable problems in terms of stock management, storage, handling and disposal of these devices. In another embodiment described in the same patent, the combined piercing and collecting device is a part of the same unit of the machine that supports the capsule. It is anyway quite clear that, if it fails to be cleaned frequently, it may well give rise to the same kind of drawbacks as already discussed with reference to EP-A-0 521 510.